A female quick coupling engageable under pressure generally comprises an outer tubular support body, a hollow valve body supported inside the support body and an obturator slidable in the valve body in the direction of the axis of the coupling so as to open and close the outlet path.
In some types of female quick couplings the obturator has a mushroom head intended to interact with a corresponding head of an obturator of a male quick coupling.
One of the main drawbacks of a female quick coupling of the type with an obturator having a mushroom head consists of the risk of early opening of the obturator which could generate uncontrolled fluid leaks before the coupling has been fully engaged under pressure. Another drawback consists of the fact that the obturator may have a configuration such that the pressure of the fluid present in the valve body may hinder the completion of the coupling engagement under pressure.